What critical piece of information is required on a medication label?

The client’s name is a critical piece of information required on a medication label because it ensures that the medication is dispensed to the correct individual. This helps to prevent medication errors and ensures that patients receive the appropriate treatment tailored to their specific health needs.

Including the client’s name on the label allows healthcare providers, pharmacists, and caregivers to verify the identity of the patient, which is essential for safe medication administration. It also helps patients themselves recognize their prescriptions, thereby enhancing adherence and understanding of their treatment regimen.

While other options such as the pharmacy address, medication cost, and prescribing physician's contact information can be important in different contexts, they do not directly serve the primary function of ensuring that the medication is correctly associated with the patient for whom it is intended.